The Prince and Astronomer

The outline of Galileo’s rise to fame is one of the most well-known stories in the history of science. How he heard about the invention of the telescope sometime in 1609 and then built an improved version of the instrument. How he began observing the heavens towards the end of the year and at the beginning of 1610 discovered the four largest moons of Jupiter, the most spectacular astronomical discovery since the beginnings of the discipline in antiquity. Realising what he had achieved, Galileo rushed into print, publishing his Sidereus Nuncius, containing an account of his discoveries in March 1610.

At the beginning the majority were justifiably sceptical about Galileo’s claims and independent collaboration of his discoveries was slow in coming. The telescopes available at the time were of very poor quality and observing with them extremely difficult. However, the Jesuit astronomers of the Collegio Romano in Rome were finally able to confirm all of Galileo’s discoveries and he was hailed as the greatest astronomer of the age. In March 1611 he undertook a triumphant journey to Rome to celebrate his newfound status. The Jesuits at the Collegio Romano held a great banquet in his honour praising both him and his discoveries. Shortly after a slightly different group, the Accademia dei Lincei, also held a banquet in his honour, inducting him as a member of their academy and giving his new wonderful instrument its name, the telescope.

Of course this immediately raises the question who or what is the Accademia dei Lincei. In most accounts of Galileo’s life we get the information that this was an early scientific society founded by the aristocrat Federico Cesi, which shared Galileo’s empirical views on science and thus inducted him into their society actively publishing his Istoria e dimostrazione intorno alle macchie solari (Letters on Sunspots) in 1613 and his Il Saggiatore (The Assayer) in 1623. Other members of the society might or might not be mentioned by name but apart from that very little gets said about them.

Who were they really? What were their aims? To what extent did they and Galileo share the same view of science? How did they relate to other major players of the age, the Catholic Church, the Jesuits? It is very rare for any of these questions to be even asked let alone answered. But they are interesting and important questions within the context of the evolution of science in Northern Italy in the early seventeenth century.

A recently published book—recent that is in English translation, it appeared in Italian three years ago—is Paolo Galluzzi’s The Lynx and the Telescope: The Parallel Worlds of Cesi and Galileo.[1] Galluzzi delivers what it says on the cover, a complete history of the Accademia dei Lincei with a central emphasis on their relations to Galileo.


It turns out that although the Lincei were proud to have Galileo as a member and more than willing to support his endeavours, Cesi’s approach to science differed substantially from that of the Tuscan astronomer. Cesi was well aware of this and refrained from showing his own studies in natural history to Galileo. The Lincei were also keen to maintain good relations with the Church and especially the Jesuits and made serious efforts behind the scenes to curb some of Galileo’s more ardent attacks on his religious opponents.

Much of the original material, in particular Cesi’s own very extensive, largely unpublished writings have been lost so Galluzzi’s book is the product of a long detective search, digging up every letter, note, reference etc. that still exists that has some sort of relevance to the Lincei and Cesi their leader. As a result his book is exhaustive and I must admit that I at least found it at times exhausting. If you really want to know about the Lincei and Cesi in great detail and only want to read one book on the subject then this is without doubt the book to read (although I would also recommend reading David Freedberg’s The Eye of the Lynx[2])

However my feelings about the book are not one hundred per cent positive. Galluzzi has been director of the Museo Galileo – Institutio e Museo di Storia della Scienza in Florence since 1982 and he is a Galileo groupie. For him Galileo can do no wrong. He states several times in the book that Galileo was motivated purely by a belief in the truth and the defence of freedom of expression. He says that those, present writer included, who claim that Galileo was to a great extent the cause of his own problems are flat out wrong. It is interesting in this context that when discussing the Il Saggiatore, for example, he makes no mention of the fact that Galileo’s accusations of plagiarism against Simon Marius or Christoph Scheiner were false and that Galileo knew them to be false. Or that in the main issue being debated, the nature of comets, that Grassi was right and Galileo flat out wrong, choosing to argue as he did only to win at all cost. A man who only championed the truth?

At one point Galluzzi delivers up something illustrating Galileo’s deviousness, which was entirely new to me. It appears that Cesi had read Kepler’s Astronomia Nova and was much taken with the simplicity of Kepler elliptical orbits when compared to the deferent-epicycle model employed by both Ptolemaeus and Copernicus. In a letter Galileo says to Cesi:

We should not wish nature to accommodate itself to what seems better ordered and disposed to us; we should rather accommodate our own intellect to what nature has made, in the certainty that this is the best and only way. And since it pleased her to make the stars move around different centres, we can be sure that such an arrangement is the most perfect and admirable and that any other would be lacking in elegance, incongruous and puerile.[3]

Galluzzi then goes on to say:

One may suspect that Galileo’s brusque reaction was aimed at a target far more sensitive to Cesi than was Lagalla [the direct subject of the discussion on epicycles]. Distancing himself from the Prince’s anthropocentric conception of nature, Galileo aimed to strike at the heart of a person of a quite different scientific calibre, an author towards whom Federico had shown an inclination: Johann Kepler, who had developed the vision of a cosmos constructed in accordance with the rules of order, mathematical proportion, rationality and harmony based on the centrality of mankind in the plan of the divine Creation.[4]

 Galluzzi then reveals his own pro Galileo bias:

It is telling that, after the discovery of the satellites of Jupiter, Kepler had wondered what influence they exerted on the inhabitants of Earth. Galileo was disappointed to discover that Cesi’s wary approach to heliocentrism was by way of the obscure paths [my emphasis] of the Imperial astronomer.

It seems to have escaped Galluzzi’s notice that Kepler’s version of heliocentrism was correct and Galileo’s wrong. Also Kepler’s comments appeared in his Conversations with Galileo’s Sidereal Messenger, which Galileo did not hesitate to publish in a pirate edition in Florence upon receiving a copy from the author.

For me it appears that Galileo will resort to any rhetorical argument, not for the first or the last time, to defend his truth against all comers rather than admit that the others might have better arguments.

Galluzzi’s groupie mentality aside, this is an important book on the milieu in which Galileo worked and created his theories and one that should be read by anyone with a deep interest in the subject. It has, as would be expected excellent footnotes, index and bibliography but being from Brill a price that no normal human being would want to pay. I borrowed it from the library.

[1] Paolo Galluzzi, The Lynx and the Telescope: The Parallel Worlds of Cesi and Galileo, Trans: Peter Mason, Brill, Leiden & Boston, 2017

[2] David Freedberg, The Eye of the Lynx: Galileo, His Friend, and the Beginnings of Modern Natural History, University of Chicago Press, Chicago & London, 2002

[3] Letter to Cesi, 30 June 1612, Galluzzi p. 114

[4] Galluzzi p. 115



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6 responses to “The Prince and Astronomer

  1. Fascinating, thank you.
    There is a small typo: “which was entirely knew to me.” It’s entirely new to me that this may happen to a native speaker; it is a very German typo….

  2. Paolo Galluzzi also figured prominently in Leonardo’s dream machines, a program about attempts to build a couple of Leonardo’s designs for real: his giant crossbow, and one of his flying machines.

  3. C. M. Graney

    I found my own complaint with this book, one that lines up with yours. In a discussion of Kepler, Galluzzi writes on how Kepler in the second decade of the 17th century had no trouble “demolishing” the “weak” anti-Copernican arguments of Francesco Ingoli, a Monsignor connected to the Roman Inquisition and one of the players in the whole debate around Copernicus in Italy at the time. See page 240 of the book ( or ). I translated Ingoli’s arguments. They were certainly not weak and not easily demolished; they were for the most part the arguments of Tycho Brahe, and Ingoli cited them as brahe’s arguments, right down to the page number. Galluzzi’s assertion there can’t be defended. That seems to go along with your assessment about a bias toward Galileo (or toward Galileo’s “side”). I’m not offering a major criticism of the book — folks should read it, by all means.

  4. Pingback: The telescope – claims and counterclaims | The Renaissance Mathematicus

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